不饱和超支化聚(酰胺-酯)改性PVC研究

对不饱和超支化聚(酰胺-酯)(HBP)与聚氯乙烯(PVC)共混体系的力学性能和相形态结构进行了研究。研究结果表明,在聚氯乙烯中加入不饱和超支化聚(酰胺-酯)可以有效提高共混体系的拉伸强度,并且在100g PVC中加入3g HBP时共混体系的拉伸强度出现最大值,抗冲强度基本不变。扫描电子显微镜(SEM)研究结果证明了HBP和PVC相容性较好,且与测得的力学结果相一致。同时,利用氢键形成机理对其结果进行了解释。     

新型超支化聚(酰胺-酯)的制备及表征

以二异丙醇胺和六氢化苯二甲酸酐为原料,合成AB_2型单体(DH)。二异丙醇胺过量,利用DH和过量的二异丙醇胺在共沸带水剂二甲苯中进行缩聚反应,合成新型超支化聚(酰胺-酯);同时利用傅立叶红外光谱和化学滴定法对DH和超支化聚(酰胺-酯)进行表征,并对超支化聚(酰胺-酯)的相对分子量分布、溶解性能进行研究。实验结果表明:合成的超支化聚(酰胺-酯)具有较高的分子量,M_n高达42769g/mol,多分散性指数在1．28～1．60之间,呈现很窄的分子量分布;合成的超支化聚(酰胺-酯)具有良好的溶解性能,能溶于醇类、酮类、四氢呋喃等极性溶剂;相对线形高分子,合成的超支化聚(酰胺-酯)具有较低的黏度,体系中含40%的超支化聚(酰胺-酯)仍能全部溶解,且黏度仅为6．61mPa·s。     

超支化聚(胺-酯)接枝改性纳米二氧化硅增韧增强PVC的研究

用偶联削KH-550和超支化聚（胺-酯）对纳米SiO2进行改性,并通过熔融共混法制得了PVC／SiO2复合材料。利用透射电镜、扫描电镜、力学性能测试等方法研究了复合材料的结构和性能。结果表明,通过超支化聚（胺-酯）的接枝改性可以明显提高纳米SiO2在PVC基体中的分散均匀性;超支化聚（胺-酯）接枝改性纳米SiO2的加入可有效提高PVC的力学性能,且添加量为1％时,效果最好,同时PVC的加工性能也有所改善。     

反应性核壳超支化嵌段共聚醚增韧环氧树脂

近年来，基于超支化聚合物（尤其是聚酯）的新型抗冲改性剂已有相关报道。由羟基、羰基以及环氧封端的超支化聚酯可以制备低黏度的共混物。加入少量这些聚酯就足以极大地提高共混物的韧性而不降低其强度以及玻璃化温度。超支化聚合物（HBP）的重要特征是其支化重复单元的极高支化度，以及聚合物核壳结构表面带有的大量功能性端基。由于高度支化的结构阻止了链缠结的发生，超支化聚合物通常在熔融态或溶液中显示出较低的黏度。超支化聚合物的性能主要受数目众多的端基影响，因此进行端基改性可以得到不同用途的超支化聚合物。     

环氧树脂/超支化聚酯/纳米SiO2复合材料的制备及性能

采用超支化聚酯与聚硅酸溶胶共混改性环氧树脂,制备了环氧树脂/超支化聚酯/纳米SiO2三元共混体系纳米复合材料。研究了超支化聚酯/聚硅酸溶胶增韧改性环氧树脂固化体系的力学性能及热性能,通过X射线衍射(WAXD)、差示扫描量热(DSC)、热重分析(TGA)及扫描电镜(SEM)等测试手段对材料的微观相态结构与性能进行了表征。结果表明,超支化聚酯/聚硅酸的加入使纳米复合材料的力学性能和热性能得到明显提高。当纳米SiO2的含量为1%(质量分数,下同)时冲击强度比纯环氧树脂提高了10.48kJ/m2,材料的起始热分解温度也提高了27℃。     

两亲性超支化聚(酰胺-酯)对染料相转移行为的研究

利用苯甲酰氯对超支化聚(酰胺-酯)端羟基修饰,合成了一种新型的以超支化聚(酰胺-酯)为亲水核,苯环为疏水壳的两亲性超支化聚(酰胺-酯)。此两亲性超支化聚合物在0.125～0.5g/L的浓度范围内能够以单分子胶束形式将甲基橙(MO)从水相转移到二氯甲烷相,转移是个动态平衡过程,呈现前快后慢的趋势,22h后转移量达到95%,转移后的甲基橙也可以被可逆释放到二氯甲烷相。此外,对甲基橙和甲基蓝(MB)的双染料转移,表明少量甲基蓝分子的存在可以使甲基橙的转移量大大增加,起到了协同转移作用。     

超支化聚(胺)酯基二茂铁/E-51环氧树脂复合材料的制备及性能

为制备结构/吸波一体化的复合材料,将超支化聚(胺)酯基二茂铁(HAPE-Fc)作为吸波剂通过物理共混与经超支化环氧(EHBP)改性的E-51环氧树脂基体复合,研究复合材料的密度、热稳定性和力学性能。结果表明,复合材料的密度较小,介于1.15 g/cm3~1.23 g/cm3之间;热稳定性较好,起始热分解温度均高于250℃,最大热分解温度均高于290℃;力学性能最好的为第二代超支化聚(胺)酯基二茂铁(G2-HAPE-Fc)添加量为5%的复合材料,拉伸强度为59.05MPa,断裂伸长率为5.77%,冲击强度为12.89kJ/m2。     

超支化聚酯/聚对苯二甲酸乙二醇酯复合材料的结构与性能

以分别具有端羟基、端十六烷基和端苯基的超支化聚酯(HBP)对聚对苯二甲酸乙二醇酯(PET)进行共混改性,研究了HBP的端基类型和用量对HBP/PET复合材料拉伸强度、冲击强度、结晶性能及动态黏弹性的影响。结果表明: 当端苯基超支化聚酯(HBP-Bz)、端十六烷基超支化聚酯(HBP-C16)和端羟基超支化聚酯(HBP-OH)的质量分数分别为0.1%、0.4%和0.2%时,HBP/PET复合材料的拉伸强度和冲击强度均达到最大值;3种超支化聚酯在其质量分数为0.1%~0.4%的范围内,复合材料的结晶度都得到了提高,与HBP-C16和HBP-OH相比,HBP-Bz的加入明显加快了PET的结晶速率;低用量(0.1wt%~0.4wt%)的HBP在PET共混改性中起到了增黏的效果,HBP/PET复合材料熔体表现出假塑性流体的流变行为,HBP的加入在一定程度上增加了PET大分子的链缠结和物理交联点,从而使HBP/PET复合材料的拉伸强度、冲击强度以及熔体黏度均得到提高。     

新型芳香型超支化聚氨酯的合成及表征

以甲苯-2,4-二异氰酸酯(TDI)、聚己二酸丁二醇酯二醇(PBA)和二乙醇胺(DEOA)为原料合成了一种新型芳香型超支化聚氨酯。采用红外光谱(FT-IR)、核磁共振(13C-NMR)对超支化聚氨酯的结构进行了表征,用凝胶渗透色谱(GPC)对其分子量进行了测定,并利用热失重分析(TGA)和拉伸剪切强度测试等手段对其热性能和粘接性能进行了测试。     

超支化聚(胺-酯)为模板Ag纳米粒子的制备

以超支化聚(胺-酯)为模板,采用NaBH4直接还原和紫外灯光照射合成了Ag纳米粒子。超支化聚(胺-酯)对Ag纳米粒子形成起着重要的作用。TEM分析表明,Ag纳米粒子形貌为球形结构,分布均匀,粒径约为45 nm(NaBH4还原)和20 nm(紫外灯光照射)。发现在UV-Vis谱图中420 nm左右有Ag纳米粒子特征表面等离子共振吸收峰。FT-IR分析发现Ag纳米粒子和超支化聚(胺-酯)之间有较强的相互作用,超支化聚(胺-酯)对Ag纳米粒子的稳定性起保护作用。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.